Overheating in Traffic 1980 Fuel Injected

[evrenosogullari]

Kind of a pain that I live in New York City, because whenever going on 90-100 mi trip anywhere it usually involves sitting in traffic on the way in / out sometimes for upwards of 10 minutes at a time on a hot summer day. Have a big problem with the temperature gauge leaning past 190 and edging towards the red when stopped. Sometimes it hits the red, I need to pull over (sometimes in nefarious places), slowly unscrew the cap and let the coolant spray out a little for 30 minutes.

Anyone believe that it's possible to get the car into good enough shape to withstand traffic?

— Going to replace the Temp sensor this week for a different reason, not sure if will help

— Fan seems to be working as it should. I get the feeling it comes on somewhere between the 190 mark and the red line though (I saw someone post that its supposed to come on at 195?)

— Radiator is pretty old, looks like maybe an original, I wonder if one of those newer aluminum ones would be better to withstand high temperatures?

Appreciate the advise if anyone has managed to deal with this in the past

Thanks!

[toyfiats]

Anyone believe that it's possible to get the car into good enough shape to withstand traffic?

Yes, a cooling system that is properly maintained and in working order will be able to cope with traffic with no problem. The fact that yours is overheating is clearly indicative that there's a problem somewhere, but throwing parts at it won't help. You (or a competent mechanic that knows how to burp a late model Fiat Spider) will need to methodically analyze the system to determine where the problem is.

[tima01864]

If the fan does kick on there should not be air in the system?

[evrenosogullari]

Yes, a cooling system that is properly maintained and in working order will be able to cope with traffic with no problem. The fact that yours is overheating is clearly indicative that there's a problem somewhere, but throwing parts at it won't help. You (or a competent mechanic that knows how to burp a late model Fiat Spider) will need to methodically analyze the system to determine where the problem is.

Thanks... I assume there's a post on here somewhere that will give me a little direction. By "burp" the system do you mean drain the coolant from the radiator (noticed yesterday that the coolant in the radiator is a dark, muddy color), and ensure that the sensors are working properly? Will be looking into this this weekend.

[aj81spider]

Dark muddy color means the coolant is long overdue for a change. It also means you may have sludge building up. I would flush the cooling system and change the coolant as a start. I'd also check all the hoses (and replace them if there is any doubt as to their age or condition).

I'm also not sure that loosening the radiator cap and letting coolant escape is either effective or safe. You run a real risk of getting burned and you're just creating a risk of introducing air into the system, while not actually accelerating the cooling process. Pull over and turn the car off and just let it sit. If you want a backup until you get the system fixed you could put a switch on the fan and switch that on when pulled over (with the car off) to help the radiator cool down.

A well maintained Fiat cooling system is more than adequate for the car, so as mentioned above overheating is the symptom of issues that need to be fixed.

[18Fiatsandcounting]

By "burp" the system do you mean drain the coolant from the radiator (noticed yesterday that the coolant in the radiator is a dark, muddy color), and ensure that the sensors are working properly?

Burping the system just means removing the last bits of air from the coolant system before closing up the radiator cap. Since the cap is lower to the ground than parts of the cylinder head, a pocket of air can get trapped in the head that is significant enough to cause a problem. Burping solves this.

There are several methods to remove that air pocket:
1) Fill the radiator with the front end of the car raised a foot or two in the air, which places the cap higher than other parts, and avoids the pocket formation in the first place. This is the easiest method.

2) Put a T-connection on the heater hose going across the exhaust camshaft cover and fill the last bits through that. This is the best method.

3) Use the overflow tank to fill the system, but this means it and the radiator cap really has to be working. And, some people have success with this, and some do not. The idea is that when the car is hot and cools back down, the radiator cap should allow fluid to be drawn from the overflow tank back into the radiator. Several cycles of this, and it helps fill the system.

As others have said, definitely drain and flush your coolant. I've got 2 engines in my garage now that I'm working on, and you wouldn't believe the stuff that comes out of the coolant passageways after years of neglect. Rust, scale, goo, etc.

-Bryan

[evrenosogullari]

Thanks so much everyone for the specific advise .... I will get started!

Also forgot to mention its been around 95 degrees here in nyc.... a real test for a the cooling system.

[maxm50]

Hey Bryan,
Another thought: On a FI engine, you've also got two small coolant lines that run to/from the throttle body heater (the absolute highest point of the cooling system when the car is level). When I've filled my system up the last 2 times, I do the bulk of the filling through the radiator cap (because it's the largest/easiest opening), then when it's full to that point I close that and fill from the plug on the coolant tee, then close that and fill the last bits through one of these throttle body heater hoses (disconnected from throttle body) using a small funnel jammed into it. Then when coolant starts flowing out of the throttle body's open port, I cover it with my thumb, then jam the hose back on. All while the car is level.

Is there any flaw in this logic? I did this to avoid cutting into a coolant hose and installing a tee. I'll bet there's no analog to this method on a carb'd engine, but it seems to work pretty well on my FI engine...

[davidbruce]

Maxm, that is close to how my IAP reprint of the fiat manual shows.
1)make sure heater valve is open and fill rad to full at cap.
2)disconnect hose from thermostat at the tee. Fill the hose until water flows from the tee and reconnect hose.
3)remove plug from tee and fill until full.
4)fill overflow tank.
5)remove small hose from heater on intake and fill through hose until it comes out of the heater. Replace the hose.
Start the car and wait for 2 fan cycles, done. This method has worked everytime for me.

But first things first. That cooling system needs to be drained and flushed. I would do it twice. There are rad flushes at the auto parts store. Some people use a little automatic dishwasher detergent. Not dishsoap! It will foam. Whatever you use, flush it thoroughly with clean water. After that I would burp as above with straight water and make sure whatever you flushed out wasn't plugging a leak that has now exposed itself. If no leaks then drain and refill with a 50-50 mix of water and quality universal anti freeze and then see how it behaves. Opening the cap is more than likely introducing air into the system and making the problem worse. If the rad leaks then don't mess around and replace the rad. I don't think a properly maintained and functional cooling system requires a fancy rad but if the price difference is nominal and it's a direct bolt in then why not? Also know that the system still needs to be flushed. I wouldn't expect the temp gauges to be 100% accurate and wouldn't panic if the cap is holding pressure and not puking out the overflow. Also check that the cap is good and the correct one. I believe there are 2 different neck length/cap depths so make sure they match. Don't go by application as the rad may not be original. Also double check the cap pressure. I believe it is 13# but check for yourself. If any of this is daunting then consider getting it done and tested by a rad shop. As was already stated. The system is more than adequate. If it is really overheating then fix it properly and drive it in peace. Good luck.

[bobplyler]

A simple suggestion:
If the engine is getting just a little overheated, you can turn on the heater full blast. The heater core is a little radiator. It can make the inside of the car hot, but in an emergency, can provide a little help.

[18Fiatsandcounting]

Max, excellent idea, and I can't see any flaw in your logic. I actually know very little about FI engines. (I'm old school)

David, lots of great suggestions, thanks for that!

Bob, you won't believe how many times running the heater in stuck traffic has saved my &%$ on a hot day. Not pleasant, but it works! Turn the heater fan on for maximum enjoyment. Feel the heat; it will cleanse your soul....

-Bryan

[evrenosogullari]

This is all above-and-beyond Thanks Much. Will drain & flush, burp and then chec for leaks with a 50-50 water/anti freeze and check hoses.

love the thing about turning the heater on – will absolutely do that this weekend if the above doesn't help.....

[18Fiatsandcounting]

Just a suggestion: I usually do the initial leak check with just water in the system, just so I don't have to go out and buy more antifreeze if there is a leak. After the cooling system passes the leak check, I drain and refill with 50/50 antifreeze/water.

As for aluminum vs. copper/brass, well, aluminum has several advantages: cheaper, lighter, less corrosion, easier to manufacture for best heat dissipation. It's main disadvantage is that it is hard to fix if there is a leak, whereas copper radiators are fairly easily to fix. Disclaimer: I've never used an aluminum radiator in a Fiat.

-Bryan

[davidbruce]

Ev I just noticed you have an automatic car. I'm not familiar with the Fiat set up but there should be cooler lines to and from the transmission/rad. If so and you do replace the rad the new one will need to have fittings for these lines or you will have to get an after market cooler and install it. You may want to ask the vendor before purchasing one.

[evrenosogullari]

Flushed it twice and managed to get the water draining out to start to look pretty clean. Now I'm noticing that the fan does not come on (could it be shorting out?) The terminals are in enclosed in a kind of cap that I couldn't get off.... Still overheating within about 10 minutes of idling from cold (side note: its literally 98º out today, the car seems to be at 190º before I even start it).

At my wits end, thinking of buying a new aluminum radiator and starting from there... checking all the connections etc. and ruling out anything defective part-by-part. Thanks David for the heads up on the external cooler for automatic. Any idea where to get one (the external cooler, I found a radiator below) and how to install it to the radiator??


https://www.vickauto.com/FIAT-PARTS/FIA ... KU-11-2320